1. Technical Field
The present invention relates to a power supply and a battery pack therein. More particularly, the present invention relates to a power supply and a battery pack having charging capabilities.
2. Description of Related Art
To various modern portable electronic products, such as MP3s, PDAs, notebook computers, electronic pocket translators, digital cameras, and so on, batteries are indispensable. Among a variety of batteries, secondary batteries, in virtue of the recharge ability, have been recognized as economically beneficial and environmentally friendly, thus being increasingly applied in a wide range of applications.
Generally, charging a secondary battery has to be performed by means of a battery charger that implements a transformer to convert the grid power supply into a charging power source having a predetermined voltage level, for charging the secondary battery. However, this approach has its inherent defect because it is difficult to access a charging power source conveniently outdoors. This defect significantly weakens the efficiency of the battery charger and in turn the power provision depends thereon, thereby inconveniencing the users.
On the other hand, with the drain of non-renewable resources, electricity has become increasingly short and costly. This drives the development of exploitation and applications of the inexhaustible green energy source. Furthermore, it is desired that those portable digital devices such as MP3s, PDAs, iPods and iPhones can be resupplied with power on the go. Hence, how to ensure power provision to the portable electronic products through simple portable batteries (e.g. one for a notebook computer), without limitations, even at places without the grid power supply, would be an issue to be addressed.